1. Field of the Invention
The present invention relates to a structure for supporting a detector head of a radiation detector, such as for example the camera head of an Anger-type scintillation gamma camera.
2. Description of the Prior Art
U.S. Pat. No. 4,417,143 describes a supporting structure for driving the camera head of an emission computerized tomography (ECT) Anger-type scintillation camera. A support arm, carrying the camera head at one end and a counterweight at the other, is mounted on a universal joint and driven about the joint by a crank. The crank comprises an acme-type screw and the arm attaches to the crank at a point distant from the joint by means of an acme nut. The tilt angle of the arm is varied the position of the acme nut on the acme screw. For compensating different distances between the point of attachment of the support arm to the crank and the universal joint under different tilt angles a relatively complicated telescoping coupling member has to be utilized for the support arm.
U.S. Pat. No. 4,216,381 illustrates another supporting structure for driving the camera head of an ECT scintillation gamma camera, which comprises an upright circular frame having an outer circular ring and a concentric inner circular ring adapted for concentric relative rotation. An elongated frame of two support arms, which supports the camera head on its one end and a counterweight on its other end between the support arms, is tiltably mounted within the inner circular ring of the circular frame.